xref: /netbsd-src/usr.bin/w/w.c (revision fa370be1c778063ddab749535f924f166e8ad354)
1 /*	$NetBSD: w.c,v 1.93 2022/05/26 06:48:36 wiz Exp $	*/
2 
3 /*-
4  * Copyright (c) 1980, 1991, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1980, 1991, 1993, 1994\
35  The Regents of the University of California.  All rights reserved.");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)w.c	8.6 (Berkeley) 6/30/94";
41 #else
42 __RCSID("$NetBSD: w.c,v 1.93 2022/05/26 06:48:36 wiz Exp $");
43 #endif
44 #endif /* not lint */
45 
46 /*
47  * w - print system status (who and what)
48  *
49  * This program is similar to the systat command on Tenex/Tops 10/20
50  *
51  */
52 #include <sys/param.h>
53 #include <sys/types.h>
54 #include <sys/time.h>
55 #include <sys/stat.h>
56 #include <sys/sysctl.h>
57 #include <sys/proc.h>
58 #include <sys/ioctl.h>
59 #include <sys/socket.h>
60 
61 #include <netinet/in.h>
62 #include <arpa/inet.h>
63 
64 #include <ctype.h>
65 #include <err.h>
66 #include <errno.h>
67 #include <fcntl.h>
68 #include <kvm.h>
69 #include <limits.h>
70 #include <netdb.h>
71 #include <nlist.h>
72 #include <paths.h>
73 #include <stdio.h>
74 #include <stdlib.h>
75 #include <string.h>
76 #include <time.h>
77 #include <tzfile.h>
78 #include <unistd.h>
79 #ifdef SUPPORT_UTMP
80 #include <utmp.h>
81 #endif
82 #ifdef SUPPORT_UTMPX
83 #include <utmpx.h>
84 #endif
85 #include <vis.h>
86 
87 #include "extern.h"
88 
89 struct timespec	boottime;
90 struct winsize	ws;
91 kvm_t	       *kd;
92 time_t		now;		/* the current time of day */
93 int		ttywidth;	/* width of tty */
94 int		argwidth;	/* width of tty left to print process args */
95 int		header = 1;	/* true if -h flag: don't print heading */
96 int		nflag;		/* true if -n flag: don't convert addrs */
97 int		wflag;		/* true if -w flag: wide printout */
98 int		sortidle;	/* sort by idle time */
99 int		alphasort;	/* sort by tty alphabeta, not numeric */
100 char	       *sel_user;	/* login of particular user selected */
101 char		domain[MAXHOSTNAMELEN + 1];
102 int maxname = 8, maxline = 3, maxhost = 16;
103 
104 /*
105  * One of these per active utmp entry.
106  */
107 struct	entry {
108 	struct	entry *next;
109 	char name[UTX_USERSIZE + 1];
110 	char line[UTX_LINESIZE + 1];
111 	char host[UTX_HOSTSIZE + 1];
112 	char type[2];
113 	struct timeval tv;
114 	dev_t	tdev;			/* dev_t of terminal */
115 	time_t	idle;			/* idle time of terminal in seconds */
116 	struct	kinfo_proc2 *tp;	/* `most interesting' tty proc */
117 	struct	kinfo_proc2 *pp;	/* pid proc */
118 	pid_t	pid;			/* pid or ~0 if not known */
119 } *ehead = NULL, **nextp = &ehead;
120 
121 static void	pr_args(struct kinfo_proc2 *);
122 static void	pr_header(time_t *, int);
123 static int	proc_compare_wrapper(const struct kinfo_proc2 *,
124     const struct kinfo_proc2 *);
125 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
126 static int	ttystat(const char *, struct stat *);
127 static void	process(struct entry *);
128 #endif
129 static void	fixhost(struct entry *ep);
130 __dead static void	usage(int);
131 
132 int
main(int argc,char ** argv)133 main(int argc, char **argv)
134 {
135 	struct kinfo_proc2 *kp;
136 	struct entry *ep;
137 	int ch, i, nentries, nusers, wcmd, curtain, use_sysctl;
138 	char *memf, *nlistf, *usrnp;
139 	const char *options;
140 	time_t then;
141 	size_t len;
142 #ifdef SUPPORT_UTMP
143 	struct utmp *ut;
144 #endif
145 #ifdef SUPPORT_UTMPX
146 	struct utmpx *utx;
147 #endif
148 	const char *progname;
149 	char errbuf[_POSIX2_LINE_MAX];
150 
151 	setprogname(argv[0]);
152 
153 	/* Are we w(1) or uptime(1)? */
154 	progname = getprogname();
155 	if (*progname == '-')
156 		progname++;
157 	if (*progname == 'u') {
158 		wcmd = 0;
159 		options = "";
160 	} else {
161 		wcmd = 1;
162 		options = "AhiM:N:nw";
163 	}
164 
165 	memf = nlistf = NULL;
166 	while ((ch = getopt(argc, argv, options)) != -1)
167 		switch (ch) {
168 		case 'A':
169 			alphasort = 1;
170 			break;
171 		case 'h':
172 			header = 0;
173 			break;
174 		case 'i':
175 			sortidle = 1;
176 			break;
177 		case 'M':
178 			header = 0;
179 			memf = optarg;
180 			break;
181 		case 'N':
182 			nlistf = optarg;
183 			break;
184 		case 'n':
185 			nflag = 1;
186 			break;
187 		case 'w':
188 			wflag = 1;
189 			break;
190 		case '?':
191 		default:
192 			usage(wcmd);
193 		}
194 	argc -= optind;
195 	argv += optind;
196 
197 	use_sysctl = (memf == NULL && nlistf == NULL);
198 
199 	if ((kd = kvm_openfiles(nlistf, memf, NULL,
200 	    memf == NULL ? KVM_NO_FILES : O_RDONLY, errbuf)) == NULL)
201 		errx(1, "%s", errbuf);
202 
203 	(void)time(&now);
204 
205 	if (use_sysctl) {
206 		len = sizeof(curtain);
207 		if (sysctlbyname("security.curtain", &curtain, &len,
208 		    NULL, 0) == -1)
209 			curtain = 0;
210 	}
211 
212 	if (!nflag) {
213 		int	rv;
214 		char	*p;
215 
216 		rv = gethostname(domain, sizeof(domain));
217 		domain[sizeof(domain) - 1] = '\0';
218 		if (rv < 0 || (p = strchr(domain, '.')) == 0)
219 			domain[0] = '\0';
220 		else
221 			memmove(domain, p, strlen(p) + 1);
222 	}
223 
224 #ifdef SUPPORT_UTMPX
225 	setutxent();
226 #endif
227 #ifdef SUPPORT_UTMP
228 	setutent();
229 #endif
230 
231 	if (*argv)
232 		sel_user = *argv;
233 
234 	nusers = 0;
235 #ifdef SUPPORT_UTMPX
236 	while ((utx = getutxent()) != NULL) {
237 		if (utx->ut_type != USER_PROCESS)
238 			continue;
239 		++nusers;
240 
241 #ifndef SUPPORT_UTMP
242 		if (wcmd == 0)
243 			continue;
244 #endif	/* !SUPPORT_UTMP */
245 
246 		if (sel_user &&
247 		    strncmp(utx->ut_name, sel_user, sizeof(utx->ut_name)) != 0)
248 			continue;
249 		if ((ep = calloc(1, sizeof(struct entry))) == NULL)
250 			err(1, NULL);
251 		(void)memcpy(ep->line, utx->ut_line, sizeof(utx->ut_line));
252 		ep->line[sizeof(utx->ut_line)] = '\0';
253 		*nextp = ep;
254 		nextp = &(ep->next);
255 
256 		if (wcmd == 0)
257 			continue;
258 
259 		(void)memcpy(ep->name, utx->ut_name, sizeof(utx->ut_name));
260 		ep->name[sizeof(utx->ut_name)] = '\0';
261 		if (!nflag || getnameinfo((struct sockaddr *)&utx->ut_ss,
262 		    utx->ut_ss.ss_len, ep->host, sizeof(ep->host), NULL, 0,
263 		    NI_NUMERICHOST) != 0) {
264 			(void)memcpy(ep->host, utx->ut_host,
265 			    sizeof(utx->ut_host));
266 			ep->host[sizeof(utx->ut_host)] = '\0';
267 		}
268 		fixhost(ep);
269 		ep->type[0] = 'x';
270 		ep->tv = utx->ut_tv;
271 		ep->pid = utx->ut_pid;
272 		process(ep);
273 	}
274 #endif
275 
276 #ifdef SUPPORT_UTMP
277 	while ((ut = getutent()) != NULL) {
278 		if (ut->ut_name[0] == '\0')
279 			continue;
280 
281 		if (sel_user &&
282 		    strncmp(ut->ut_name, sel_user, sizeof(ut->ut_name)) != 0)
283 			continue;
284 
285 		/* Don't process entries that we have utmpx for */
286 		for (ep = ehead; ep != NULL; ep = ep->next) {
287 			if (strncmp(ep->line, ut->ut_line,
288 			    sizeof(ut->ut_line)) == 0)
289 				break;
290 		}
291 		if (ep != NULL)
292 			continue;
293 
294 		++nusers;
295 
296 		if (wcmd == 0)
297 			continue;
298 
299 		if ((ep = calloc(1, sizeof(struct entry))) == NULL)
300 			err(1, NULL);
301 		(void)memcpy(ep->name, ut->ut_name, sizeof(ut->ut_name));
302 		(void)memcpy(ep->line, ut->ut_line, sizeof(ut->ut_line));
303 		(void)memcpy(ep->host, ut->ut_host, sizeof(ut->ut_host));
304 		ep->name[sizeof(ut->ut_name)] = '\0';
305 		ep->line[sizeof(ut->ut_line)] = '\0';
306 		ep->host[sizeof(ut->ut_host)] = '\0';
307 		fixhost(ep);
308 		ep->tv.tv_sec = ut->ut_time;
309 		*nextp = ep;
310 		nextp = &(ep->next);
311 		process(ep);
312 	}
313 #endif
314 
315 #ifdef SUPPORT_UTMPX
316 	endutxent();
317 #endif
318 #ifdef SUPPORT_UTMP
319 	endutent();
320 #endif
321 
322 	if (header || wcmd == 0) {
323 		pr_header(&now, nusers);
324 		if (wcmd == 0)
325 			exit (0);
326 	}
327 
328 	if ((kp = kvm_getproc2(kd, KERN_PROC_ALL, 0,
329 	    sizeof(struct kinfo_proc2), &nentries)) == NULL)
330 		errx(1, "%s", kvm_geterr(kd));
331 
332 	/* Include trailing space because TTY header starts one column early. */
333 	for (i = 0; i < nentries; i++, kp++) {
334 
335 		for (ep = ehead; ep != NULL; ep = ep->next) {
336 			if (ep->tdev != 0 && ep->tdev == kp->p_tdev &&
337 			    kp->p__pgid == kp->p_tpgid) {
338 				/*
339 				 * Proc is in foreground of this
340 				 * terminal
341 				 */
342 				if (proc_compare_wrapper(ep->tp, kp))
343 					ep->tp = kp;
344 				break;
345 			}
346 			if (ep->pid != 0 && ep->pid == kp->p_pid) {
347 				ep->pp = kp;
348 				break;
349 			}
350 		}
351 	}
352 
353 	if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 &&
354 	    ioctl(STDERR_FILENO, TIOCGWINSZ, &ws) == -1 &&
355 	    ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == -1) || ws.ws_col == 0)
356 		ttywidth = 79;
357 	else
358 		ttywidth = ws.ws_col - 1;
359 
360 	if (!wflag && maxhost > (ttywidth / 3))
361 		maxhost = ttywidth / 3;
362 
363 	argwidth = printf("%-*s TTY     %-*s %*s  IDLE WHAT\n",
364 	    maxname, "USER", maxhost, "FROM",
365 	    7 /* "dddhhXm" */, "LOGIN@");
366 	argwidth -= sizeof("WHAT\n") - 1 /* NUL */;
367 	argwidth = ttywidth - argwidth;
368 	if (argwidth < 4)
369 		argwidth = 8;
370 	if (wflag)
371 		argwidth = -1;
372 
373 	/* sort by idle time */
374 	if (sortidle && ehead != NULL) {
375 		struct entry *from = ehead, *save;
376 
377 		ehead = NULL;
378 		while (from != NULL) {
379 			for (nextp = &ehead;
380 			    (*nextp) && from->idle >= (*nextp)->idle;
381 			    nextp = &(*nextp)->next)
382 				continue;
383 			save = from;
384 			from = from->next;
385 			save->next = *nextp;
386 			*nextp = save;
387 		}
388 	}
389 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
390 	else if (ehead != NULL && alphasort) {
391 		struct entry *from = ehead, *save;
392 
393 		ehead = NULL;
394 		while (from != NULL) {
395 			for (nextp = &ehead;
396 			    (*nextp) && strcmp(from->line, (*nextp)->line) > 0;
397 			    nextp = &(*nextp)->next)
398 				continue;
399 			save = from;
400 			from = from->next;
401 			save->next = *nextp;
402 			*nextp = save;
403 		}
404 	}
405 #endif
406 
407 	for (ep = ehead; ep != NULL; ep = ep->next) {
408 		if (ep->tp != NULL)
409 			kp = ep->tp;
410 		else if (ep->pp != NULL)
411 			kp = ep->pp;
412 		else if (ep->pid != 0) {
413 			if (curtain)
414 				kp = NULL;
415 			else {
416 				warnx("Stale utmp%s entry: %s %s %s",
417 				    ep->type, ep->name, ep->line, ep->host);
418 				continue;
419 			}
420 		}
421 		usrnp = (kp == NULL) ? ep->name : kp->p_login;
422 		(void)printf("%-*s %-7.7s %-*.*s ",
423 		    maxname, usrnp, ep->line,
424 		    maxhost, maxhost, ep->host);
425 		then = (time_t)ep->tv.tv_sec;
426 		pr_attime(&then, &now);
427 		pr_idle(ep->idle);
428 		pr_args(kp);
429 		(void)printf("\n");
430 	}
431 	exit(0);
432 }
433 
434 static void
pr_args(struct kinfo_proc2 * kp)435 pr_args(struct kinfo_proc2 *kp)
436 {
437 	char **argv;
438 	int left;
439 
440 	if (kp == 0)
441 		goto nothing;
442 	left = argwidth;
443 	argv = kvm_getargv2(kd, kp, (argwidth < 0) ? 0 : argwidth);
444 	if (argv == 0) {
445 		fmt_putc('(', &left);
446 		fmt_puts((char *)kp->p_comm, &left);
447 		fmt_putc(')', &left);
448 		return;
449 	}
450 	while (*argv) {
451 		fmt_puts(*argv, &left);
452 		argv++;
453 		fmt_putc(' ', &left);
454 	}
455 	return;
456 nothing:
457 	putchar('-');
458 }
459 
460 static void
pr_header(time_t * nowp,int nusers)461 pr_header(time_t *nowp, int nusers)
462 {
463 	double avenrun[3];
464 	time_t uptime;
465 	int days, hrs, mins;
466 	int mib[2];
467 	size_t size, i;
468 	char buf[256];
469 
470 	/*
471 	 * Print time of day.
472 	 */
473 	(void)strftime(buf, sizeof(buf), "%l:%M%p", localtime(nowp));
474 	buf[sizeof(buf) - 1] = '\0';
475 	(void)printf("%s ", buf);
476 
477 	/*
478 	 * Print how long system has been up.
479 	 * (Found by looking getting "boottime" from the kernel)
480 	 */
481 	mib[0] = CTL_KERN;
482 	mib[1] = KERN_BOOTTIME;
483 	size = sizeof(boottime);
484 	if (sysctl(mib, 2, &boottime, &size, NULL, 0) != -1 &&
485 	    boottime.tv_sec != 0) {
486 		uptime = now - boottime.tv_sec;
487 		uptime += 30;
488 		if (uptime > SECSPERMIN) {
489 			days = uptime / SECSPERDAY;
490 			uptime %= SECSPERDAY;
491 			hrs = uptime / SECSPERHOUR;
492 			uptime %= SECSPERHOUR;
493 			mins = uptime / SECSPERMIN;
494 			(void)printf(" up");
495 			if (days > 0)
496 				(void)printf(" %d day%s,", days,
497 				    days > 1 ? "s" : "");
498 			if (hrs > 0 && mins > 0)
499 				(void)printf(" %2d:%02d,", hrs, mins);
500 			else {
501 				if (hrs > 0)
502 					(void)printf(" %d hr%s,",
503 					    hrs, hrs > 1 ? "s" : "");
504 				if (mins > 0)
505 					(void)printf(" %d min%s,",
506 					    mins, mins > 1 ? "s" : "");
507 			}
508 		}
509 	}
510 
511 	/* Print number of users logged in to system */
512 	(void)printf(" %d user%s", nusers, nusers != 1 ? "s" : "");
513 
514 	/*
515 	 * Print 1, 5, and 15 minute load averages.
516 	 */
517 	if (getloadavg(avenrun, sizeof(avenrun) / sizeof(avenrun[0])) == -1)
518 		(void)printf(", no load average information available\n");
519 	else {
520 		(void)printf(", load averages:");
521 		for (i = 0; i < (sizeof(avenrun) / sizeof(avenrun[0])); i++) {
522 			if (i > 0)
523 				(void)printf(",");
524 			(void)printf(" %.2f", avenrun[i]);
525 		}
526 		(void)printf("\n");
527 	}
528 }
529 
530 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
531 static int
ttystat(const char * line,struct stat * st)532 ttystat(const char *line, struct stat *st)
533 {
534 	char ttybuf[MAXPATHLEN];
535 
536 	(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
537 	return stat(ttybuf, st);
538 }
539 
540 static void
process(struct entry * ep)541 process(struct entry *ep)
542 {
543 	struct stat st;
544 	time_t touched;
545 	int max;
546 
547 	if ((max = strlen(ep->name)) > maxname)
548 		maxname = max;
549 	if ((max = strlen(ep->line)) > maxline)
550 		maxline = max;
551 	if ((max = strlen(ep->host)) > maxhost)
552 		maxhost = max;
553 
554 	ep->tdev = 0;
555 	ep->idle = (time_t)-1;
556 
557 #ifdef SUPPORT_UTMP
558 	/*
559 	 * Hack to recognize and correctly parse
560 	 * ut entry made by ftpd. The "tty" used
561 	 * by ftpd is not a real tty, just identifier in
562 	 * form ftpPID. Pid parsed from the "tty name"
563 	 * is used later to match corresponding process.
564 	 * NB: This is only used for utmp entries. For utmpx,
565 	 * we already have the pid.
566 	 */
567 	if (ep->pid == 0 && strncmp(ep->line, "ftp", 3) == 0) {
568 		ep->pid = strtol(ep->line + 3, NULL, 10);
569 		return;
570 	}
571 #endif
572 	if (ttystat(ep->line, &st) == -1)
573 		return;
574 
575 	ep->tdev = st.st_rdev;
576 	/*
577 	 * If this is the console device, attempt to ascertain
578 	 * the true console device dev_t.
579 	 */
580 	if (ep->tdev == 0) {
581 		int mib[2];
582 		size_t size;
583 
584 		mib[0] = CTL_KERN;
585 		mib[1] = KERN_CONSDEV;
586 		size = sizeof(dev_t);
587 		(void) sysctl(mib, 2, &ep->tdev, &size, NULL, 0);
588 	}
589 
590 	touched = st.st_atime;
591 	if (touched < ep->tv.tv_sec) {
592 		/* tty untouched since before login */
593 		touched = ep->tv.tv_sec;
594 	}
595 	if ((ep->idle = now - touched) < 0)
596 		ep->idle = 0;
597 }
598 #endif
599 
600 static int
proc_compare_wrapper(const struct kinfo_proc2 * p1,const struct kinfo_proc2 * p2)601 proc_compare_wrapper(const struct kinfo_proc2 *p1,
602     const struct kinfo_proc2 *p2)
603 {
604 	struct kinfo_lwp *l1, *l2;
605 	int cnt;
606 
607 	if (p1 == NULL)
608 		return 1;
609 
610 	l1 = kvm_getlwps(kd, p1->p_pid, 0, sizeof(*l1), &cnt);
611 	if (l1 == NULL || cnt == 0)
612 		return 1;
613 
614 	l2 = kvm_getlwps(kd, p2->p_pid, 0, sizeof(*l1), &cnt);
615 	if (l2 == NULL || cnt == 0)
616 		return 0;
617 
618 	return proc_compare(p1, l1, p2, l2);
619 }
620 
621 static void
fixhost(struct entry * ep)622 fixhost(struct entry *ep)
623 {
624 	char host_buf[sizeof(ep->host)];
625 	char *b, *m, *p, *r, *x;
626 	struct hostent *hp;
627 	union {
628 		struct in_addr l4;
629 		struct in6_addr l6;
630 	} l;
631 
632 	strlcpy(host_buf, *ep->host ? ep->host : "-", sizeof(host_buf));
633 	p = host_buf;
634 
635 	/*
636 	 * One ':' in hostname means X display number, more is IPv6.
637 	 */
638 	for (x = p; x < &host_buf[sizeof(host_buf)]; x++)
639 		if (*x == '\0' || *x == ':')
640 			break;
641 	if (x == p + sizeof(host_buf) || *x != ':')
642 		m = x = NULL;
643 	else {
644 		for (m = x + 1; m < &host_buf[sizeof(host_buf)]; m++)
645 			if (*m == '\0' || *m == ':')
646 				break;
647 		if (m == p + sizeof(host_buf) || *m != ':') {
648 			*x++ = '\0';
649 			m = NULL;
650 		} else
651 			x = NULL;
652 	}
653 
654 	/*
655 	 * Leading '[' indicates an IP address inside brackets.
656 	 */
657 	b = NULL;
658 	if (!nflag && (*p == '[')) {
659 		for (b = p++; b < &host_buf[sizeof(host_buf)]; b++)
660 			if (*b == '\0' || *b == ']')
661 				break;
662 		if (b < &host_buf[sizeof(host_buf)] && *b == ']') {
663 			*b = '\0';
664 			for (x = b + 1; x < &host_buf[sizeof(host_buf)]; x++)
665 				if (*x == '\0' || *x == ':')
666 					break;
667 			if (x < &host_buf[sizeof(host_buf)] && *x == ':')
668 				*x++ = '\0';
669 		} else
670 			b = NULL;
671 	}
672 
673 	int af = m ? AF_INET6 : AF_INET;
674 	size_t alen = m ? sizeof(l.l6) : sizeof(l.l4);
675 	if (!nflag && inet_pton(af, p, &l) &&
676 	    (hp = gethostbyaddr((char *)&l, alen, af)))
677 		r = hp->h_name;
678 	else {
679 		if (b)
680 			*b = ']';
681 		r = host_buf;
682 	}
683 
684 	if (domain[0] != '\0') {
685 		p = r;
686 		p += strlen(r);
687 		p -= strlen(domain);
688 		if (p > r &&
689 		    strcasecmp(p, domain) == 0)
690 			*p = '\0';
691 	}
692 
693 	if (x)
694 		(void)snprintf(ep->host, sizeof(ep->host), "%s:%s", r, x);
695 	else
696 		strlcpy(ep->host, r, sizeof(ep->host));
697 }
698 
699 static void
usage(int wcmd)700 usage(int wcmd)
701 {
702 
703 	if (wcmd)
704 		(void)fprintf(stderr,
705 		    "Usage: %s [-Ahinw] [-M core] [-N system] [user]\n",
706 		    getprogname());
707 	else
708 		(void)fprintf(stderr, "Usage: %s\n", getprogname());
709 	exit(1);
710 }
711